Sampling apparatus



April 12, 1966 s. ROSENBAUM ETAL SAMPLING APPARATUS Filed Aug. 2, 1963 United States Patent SAMPLING APPARATUS Shlomo Rosenbaum, Williamsburg, Stewart W. Burt, Newport News, and Gerald L. Losser, Williamsburg, Va., assignors to The Dow Chemical Company, Midland, Mich., a corporation of Delaware Filed Aug. 2, 1963, Ser. No. 299,623 8 Claims. (Cl. 73421) This invention relates to sampling apparatus and more particularly to sampling apparatus useful for studying the rate and equilibria of dye uptake. It permits the periodic taking of samples, in a rapid manner, of a dye solution during action upon textile material so that the rate of dye uptake can be followed during the entire course of the dye reaction up to, and including equilibrium.

For best dye rate and uptake studies, maximum reproducibility and reliability is always desired and this necessitates close control over temperature, dye bath volume, and reproducible, relative motion between fiber and bath. The usual agitation of fiber, by hand, through dye baths in open beakers sitting on hot plates or in a water bath will not accomplish good reproducibility or reliability.

Furthermore, it is always desirable to follow the progress of dye reaction with the lapse of time. This is impossible if only one dyeing is carried out, especially by hand, for a fixed period of time with subsequent examination of shade or percent exhaustion. Even if it were, the reliability of the value obtained is doubtful. Nonetheless, such procedure-s are commonly practiced.

On the other hand, work in which a separate dyeing is carried out for each point on a dye uptake versus time curve as discussed in the Journal of Society of Dyers and Colorists, vol. 50, page 381 (1934), must, of necessity, be limited in scope.

In the past, many methods have been used for following the course of a dye reaction. These methods divide rather sharply into two classes dependent upon whether the work is of a fundamental or of a practical nature. Both methods have their deficiences.

The simplified practical methods customarily used in dye houses and plant laboratories do not enable close enough control over experimental conditions, so that the results there obtained are often diflicult to interpret and frequently quantitatively invalid. Indeed, the less controlled practical methods do not reflect conditions in commercial practice. It is important that the data obtained be internally consistent and reliable and that as much as possible be learned of the effect of variables so that explanation and prediction of changes in dyehouse results can be given. Such consistency and reliability are normally not achieved in beaker dyeings.

For the fundamental studies, the apparatus utilized is generally costly to acquire and to operate. Generally, one or more spectrophotometers, dyeometers or other color measuring devices are needed (see Journal of the Society of Dyers and Col-orists, vol. 62, page 132, 1946) but most of this equipment introduces a high cost factor into any dye reaction study program instituted. And since the better studies require a separate dyeing for each point on an absorption-time curve to be reliable, additional costs are introduced by reason of the time consumption involved.

All in all, this desirability for a simple, reliable and consistent technique and apparatus with a wide range of applicability and minimum limitation on variables such as dye class, dye bath concentration, temperature, pressure and the like leaves much to be desired in the way of instrumentation currently available to the trade.

" An object of this invention is to provide a novel sampling apparatus and method for determining rate and equilibria of dye uptake.

A further object is to provide a sampling apparatus, of the above character, which is simple to operate thereby permitting continued sampling of the dye system at various stages in its reaction until equilibria is reached, thereby permitting continuous observation and even control over the dye reaction.

A. still further object is to provide sampling apparatus which, because of its ease of opera'b'ility, is widely useful in both laboratory and plant dye study work.

Another object is to provide sampling apparatus which, by reason of its design, promotes maximum reproducibility and reliability between dilierent samplings of the same dye system.

Another object is to provide sampling apparatus of the above character which has a wide range of applicability while, at the same time, has minimal limitations on variables such as dye class, dye bath concentration, temperature and pressure.

Another object is to provide a sampling apparatus of the above character which is simple to clean.

Another object is to provide a sampling apparatus of the above character which is simple to load.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The apparatus of this invention, as seen in FIG. 1, broadly comprises a reaction vessel 10 which communicates with a unique plural valve mechanism 18, so designed that pressure created inside the vessel 10, during the dye reaction delivers solution samples, via dip tube 28, directly into a modified absorption cell 36, which is detachably secured to the plural valve mechanism 18. More particularly, the apparatus herein comprises a reaction vessel 10, preferably a modified Erlenmeyer flask, having at least two closed side tubes 12 and 14 so oriented that eflicient agitation is provided for the dye bath contained within the flask when the entire flask is agitated. The mouth 16 of the reaction vessel is preferably formed as one member of a ground glass or vacuum seal joint which connects with the plural valve mechanism 18. The valve mechanism provides for the periodic taking of samples from the reaction vessel contents directly into a sample removal container, such as a modified spectrophotometer or colorimeter absorption cell 36 which is mounted on the valve mechanism via a ground glass or vacuum seal joint. The valve mechanism also provides for subsequent return of the sample from the absorption oell back into the reaction vessel, for release of pressure within the vessel when necessary and for the addition of modifiers to the dye bath to vary the dye reaction.

Temperature control over the contents of the reaction vessel is maintained by the use of a constant temperature shaker which in conjunction with the shape of the reaction vessel simultaneously provides uniform agitation of the dye bath. To keep the volume constant, the apparatus utilizes a set of covers which are tightly clamped in place.

One dyeing is suflicient for the measurement of the complete absorption-time curve since solution samples used for measurements are not diluted and can be returned to the flask shortly after withdrawal. Experimental time is further reduced by special methods of sample withdrawal and measurement. One spectrophotometer or other color measuring instrument serves for the measurement of a number of dyeings that will depend on the number of points desired on the absorptiontime curves. The range of solution concentrations measurable without dilution is widened by utilization of spectra.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

FIG. 1 is a side elevational view of one embodiment of the sampling apparatus of this invention.

FIG. 2 is a top cross-sectional view of the apparatus taken along the lines 22 of FIG. 1.

FIG. 3 is a perspective view showing the apparatus of FIG. 1 in use in a constant temperature shaking mechanism during the course of a dye reaction.

Similar reference characters refer to similar parts throughout the several views of the drawing.

As shown in FIG. 1, the sampling apparatus comprises a reaction vessel 10, preferably a modified Erlenmeyer flask, or a round bottom flask, or similar standard laboratory ware modified to etfect good agitation when shaken in a shaker tray such as shown and discussed below. The modification of the Erlenmeyer flask involves fusing of two closed-ended glass tubes to the side wall of the flask at an upward angle (FIG. 1) and directed away from the front of the fiask (see FIG. 2) as wings 12 and 14.

The mouth 16 of the reaction vessel preferably comprises the male element of a ground glass closure.

Sitting on this month via a corresponding female element 17 of the ground glass closure is a unique valve mechanism 18. Clamp 20 locks the ground glass closure against the pressure generated within the reaction vessel during the dye reaction.

Valve mechanism 18 contains a sampling valve 22 and a bleed valve 24. Within sampling valve 22 is a T-shaped bore 26, which, when in the position in FIG. 1, effects sampling of the contents of the reaction vessel via dip tube 28 which preferably is integral with the body of the valve mechanism 18.

When the bore is reversed so that the leg of the T- shaped bore faces to the right, as seen in the drawing, it communicates with dip tube pressure release arm 36. By simultaneously or subsequently opening valve 24, the pressure within the reaction vessel is released so that it is no longer effective to deliver a sample of the contents. Since the pressure in the tube and the vessel contents is equalized, any material left in the dip tube 28 then drains back into the reaction media. The sample taken may also be returned to the reaction media through the use of said sampling valve after release of pressure.

The upper portion of the valve mechanism comprises the female element 32 of a ground glass joint. The male element 34 of the joint comprises the lower portion of one or more absorption cells 36. A constriction 38 exists within male element 34 which utilizes surface tension to prevent leakage of any sample withdrawn during manipulation of the absorption cell 36. Cap 40 supplements the action of this constriction to positively insure against leakage during handling of the cell 36.

Stopper 42 for female element 32 is utilized whenever the cell 36 has been removed.

In the usual arrangement, the absorption cell is a typical 10 millimeter optical path length cell modified to allow for sample withdrawal through its base via male element 34. It preferably is formed with an upper safety reservoir 44 to insure against accidental overfilling. Its upper end comprises the male element 46 of a Wide bore ground glass joint. Cap 48 of matching female configuration provides for upper closure of the cell.

As shown, the cell is so shaped that it will fit into a Beckman DK-Z Spectrophotometer which is quite common. Its shape also permits its use with a Bausch and Lomb Spectronic 505.

Other modifications to the shape of the absorption cell or the use of auxiliary apparatus may be necessary to adapt the cell to the particular color measuring instrument being used. Conversely, the cavity within the color measuring instrument used may be altered to properly enclose the modified absorption cell.

FIG. 3 illustrates use of the reaction vessel with an attached valve mechanism 18 and an absorption cell 36 during a dye reaction. As shown, the vessel 10 is secured to shaking tray 52 via clamps 54. The tray 52 constitutes part of a constant temperature shaking mechanism 56 such as sold by American Instrument Company. Transparent cover 58 encloses the constant temperature atmosphere.

To illustrate the method and the use of the sampling apparatus, reference is now made to the following examples:

EXAMPLE I One hundred ml. of dye solution of the desired concentration were pipetted into eight separate reaction vessels It). The joints of each were greased with high vacuum silicone grease, covers fitted on and clamps 20 tightened. The assemblies were then clamped into the shaker tray 52 which was already controlled at 95.0 C. and two minutes later the pressure of each cell was released through stopcocks 24. After about 30 minutes of shaking without fiber, the absorbance of each solution was measured to obtain the experimental initial concentration, which may ditfer from that actually introduced.

To this end, a spectrophotometer absorption cell 36 was placed on top of a reaction vessel and the sampling valve 22 was then opened as in FIG. 1. When the solution reached the desired height, the valve was closed, the cell covered and removed. Bleed valve 24, then sampling valve 22 was opened until the liquid in the dip tube 28 dropped to the normal level after which both valves were closed and shaking resumed.

With the bottom cap 40 on the cell 36, it was cooled in running water, then placed in a spectrophotometer. After recording the absorbance at the appropriate peak with the usual proper spacers the shaker 56 was stopped, the solution returned, a second cell placed on the next assembly, and the procedure repeated. Scoured fibers (1.00 g.) were noW introduced by removing the valve mechanism 18 which was then replaced, the time of introduction was noted for each fiber, time spacings being determined by the number and time of the subsequent points on the sorption-time curve. Allowing three minutes per point, the scheme in Table I has been used.

Table I 0 5 10 15 25 6O 90 3 s 13 1s 2s 63 93 26 31 as 41 51 st; 116 29 31 so 44 54 so 119 52 57 02 e7 77 112 142 0 5 10 15 25 so 90 s s 13 1s 2s 03 9s 2s 31 3s 41 51 86 116 29 34 39 44 54 39 119 52 57 s2 s7 77 112 142 With it, six or seven points each on eight sorption-time curves were obtained in a total time of about four hours. More leisurely schemes have also been used, but there is no need to go more slowly than five minutes per point. Any time that a measurement was to be taken, the procedure already outlined for the empty dyebath was followed. After the last point, the fibers were rinsed, subjected to a wash test, and, after again thoroughly rinsing, to a lightfastness test.

EXAMPLE II If it is found with any dye that there are no initial changes in absorbance without fiber, the check of absorbance before fiber introduction is obviously not necessary. If the absorbance does not become constant after a short time on the other hand, and if this is not remedied by a change in dyeing conditions, such as pH, the dye is either avoided for quantitative study or the side reac- .5 tion has to be studied separately; for less quantitative Work a suitable correction factor may be adequate. In practice, the stability of the dye is best checked before the dye is used, under the conditions and for the longest period of time that the dye will be in the dyebath.

The over-all procedure before use of a dye will be illustrated with Malachite Green. If pure dye is dissolved in water and the resulting solution heated, there is a continuous decrease in concentration with time. This is due to formation of the carbinol at the pH of the solution.

VARIATION OF MALACHITE GREEN ABSORBANCE WITH pH At very low pH, the singly charged dye (I) is changed to the doubly charged, colorless (II), then to a triply charged, yellow species (III). carbinol (IV) is formed. When the solution was butfered with 0.07 m. acetate buffer to a pH of 4.2, the solutions were stable for at least a week at 98 C. There were occasionally small decreases in absorbance at the very beginning, due at least in part to limited but tenacious adsorption of Malachite Green on the glass. Errors due to it were eliminated by computing the initial concentration from the absorbance, after the solution had become stable.

Using the calibrated cells and spacers, the absorbance was measured on a DK2 Beckman Spectrophotometer over the whole concentration range of interest using 474 111,41. minimum wavelength spectrophotometer and silica spacers for the most concentrated solutions and 100 mm. cells at the 614 my. peak for the most dilute. Beers law was found to be obeyed over the whole range.

The relationship between absorbance and concentration is expressed as A=ecl (Beers and Lam-berts law), where s is a constant for a given wavelength, A is absorbance, c is concentration, and l is the path length which the light has to travel through the solution. If I is kept constant and equal to one by employing a cell of one centimeter internal width, then, at a given wavelength, absorbance (A) is directly proportional to concentration (0).

The constant e is determined by measuring the absorbance of solutions of known concentrations of dyes at a given wavelength. The dye concentration in a particular solution can then be determined by measuring the absorbance at the wavelength at which 6 was originally determined.

The absorbance at any wavelength can be recorded automatically by a spectrophotometer such as the Beckman DK2. The absorbance range that can be measured most accurately by the instrument is between 0.4 and 1.2. Within this range, the wavelengths at which absorbance can be measured most accurately are at the maxima and minirna points, e.g., Malachite Green 474 m equals minimum wavelengths, 424 my, 614 mu equals maximum wavelength. At these points, an error in wavelength will cause the least error in deter-mining absorbance.

If a particular solution concentration is determined to be outside the accurate absorbance range, the absorbance can be adiusted to be within the range by the use of spacers and/ or the choice of wavelengths. For example, if the absorbance of a dye solution is greater than 1.2 at 614 mg, the solution may be diluted by inserting a silica At high pH, the colorless I n on HO O I IV There is considerable latitude in the basic procedure to allow for changes required for specific problems. Dyeing auxiliaries can be added to the bath, either at the beginning or by addition through dip tube 28 at any stage of the dyeing, in the same manner that dye solution is returned to the bath after measurement. Similarly, if it is found necessary to allow the fiber to wet, swell, or undergo other changes before dyeing, the dye (if stable) can be added at a later stage. No need has been found for holding the fiber in a special Way in the flask. It has been used successfully as tow, staple, yarn, woven, or knitted materials. If desired, glass hooks can be blown onto the lower part of dip tube 28 and yarn wound around them. Such constraint is likely, however, to result in uneven dyeings. The liquor ratio can be varied to an extent depending on the physical form of the fiber; it is limited only by hindrance to circulation when the whole flask becomes filled with loose fiber. Where necessary, it is possible to use larger flasks, for which a diiferent shaker tray is available (Aminco) It should be possible to use a colorimeter instead of a spectrophotometer, as long as the necessary changes in the cell can be made.

The temporary decrease in liquor ratio when solution samples are withdrawn may introduce a small error. Although most of the work was done on acrylic fiber dyeings for which it was shown that diffusion occurred from a saturated or almost saturated surface layer so that the efiect could readily be neglected. In general, it should be less than the spectrophotometric error and should be similar on all dyeings being compared. It could be reduced further 'by increasing the bath ratio. It could also be corrected for, since the direction and magnitude of the change is known, but this should not normally be necessary.

For pressure dyeing, it is necessary to use thicker glass and to make special provision for the return of solution samples.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of 7 the scope of the invention, which, as a matter of language, might be said to fall therebetween.

Having described our invention, what we claim as new and desire to secure by Letters Patent is:

1. A sampling apparatus especially useful for studying the rate and equilibria of dye uptake comprising a reaction vessel having an opening mouth, and a plural valve mechanism with means to fit the mouth of said reaction vessel, and sample removal container means adapted to be removably afiixed with said valve mechanism, said plural valve mechanism having a bleed valve for establishing communication between the reaction vessel and the atmosphere, a sampling valve and a dip tube communicating with said sampling valve and extending into said reaction vessel when said valve mechanism is fitted to the mouth of said reaction vessel, said sampling valve being arranged so that in one position communication between the upper end of the dip tube and the sample removal container means is established and in another position communication between the upper end of the dip tube and the bleed valve is established, whereby samples of the medium in the reaction vessel can be removed into said sample removal container means by simple manipulation of said bleed valve and said sampling valve.

2. The sampling apparatus of claim 1 wherein the reaction vessel has means for effecting uniform agitation of the contents of the vessel.

3. The sampling apparatus of claim 1 wherein said sample removal container means comprises an absorption cell adapted for use in a spectrophotometer.

4. The sampling apparatus of claim 1 wherein said sample removal container means comprises an absorption cell adapted for use in a colorimeter.

5. The sampling apparatus of claim 1 wherein the reaction vessel, the valve mechanism and the sample removal container means are interfitted by the use of ground glass joints.

6. A sampling apparatus especially useful for studying the rate and equilibria of dye uptake comprising a reaction vessel having an opening mouth, and a plural valve mechanism with means to fit the mouth of said reaction vessel, said plural valve mechanism having a bleed valve for establishing communication between the reaction vessel and the atmosphere, a sampling valve, a dip tube pressure release passage communicating with said sampling valve and the interior of the vessel and a dip tube communicating with said sampling valve and extending into said reaction vessel when said valve mechanism is fitted to the mouth of said reaction vessel, said sampling valve being arranged so that in one position communication between the upper end of the dip tube and the pressure release passageway is established and in another position communication between the upper end of the dip tube and the exterior of the vessel is established, whereby samples of the medium in the reaction vessel can be removed and returned after testing to the reaction medium by simple manipulation of said bleed valve and said sampling valve.

7. A sampling apparatus especially useful for studying the rate and equilibria of dye uptake comprising a reaction vessel having a ground glass opening mouth, a plural valve mechanism with ground glass means to fit the ground glass opening mouth of said reaction vessel and an absorption cell with a ground glass fitting means adapted to be associated with corresponding ground glass means on said valve mechanism, said plural valve mechanism having a bleed valve for establishing communication between the reaction vessel and the atmosphere, a sampling valve, a dip tube pressure release passage communicating with said sampling valve and the interior of the vessel and a dip tube communicating with said sampling valve and extending into said reaction vessel substantially to the bottom thereof when said valve mechanism is fitted to the mouth of said reaction vessel, said sampling valve being arranged so that in one position communication between the upper end of the dip tube and the pressure release passageway is established and in another position communication between the upper end of the dip tube and the exterior of the vessel is established, whereby samples of the medium in the reaction vessel can be removed and returned after testing to the reaction medium without dilution by simple manipulation of said bleed valve and said sampling valve.

8. The sampling apparatus of claim 7 wherein the sampling valve has a T-shaped bore which is positionably adjustable so that in one position a leg thereof establishes communication between the upper end of the dip tube and the exterior of said vessel and in another position said leg establishes communication between the upper end of said dip tube and said pressure release passageway, to permit sampling, equalization of pressure in the dip tube with that in the reaction vessel and return of samples taken.

References Cited by the Examiner UNITED STATES PATENTS 2,215,594 9/1940 Parsons 73421 X 2,539,082 1/1951 Hustinx 23-259 X 2,797,150 6/1957 Regby 7342l X FOREIGN PATENTS 1,011,582 6/1957 Germany.

LOUIS R. PRINCE, Primary Examiner.

RICHARD QUEISSER, Examiner. 

1. A SAMPLING APPARATUS ESPECIALLY USEFUL FOR STUDYING THE RATE AND EQUILIBRIA OF DYE UPTAKE COMPRISING A REACTION VESSEL HAVING AN OPENING MOUTH, AND A PLURAL VALVE MECHANISM WITH MEANS TO FIT THE MOUTH OF SAID REACTION VESSEL, AND SAMPLE REMOVAL CONTAINER MEANS ADAPTED TO BE REMOVABLY AFFIXED WITH SAID VALVE MECHANISM, SAID PLURAL VALVE MECHANISM HAVING A BLEED VALVE FOR ESTABLISHING COMMUNICATION BETWEEN THE REACTION VESSEL AND THE ATMOSPHERE, A SAMPLING VALVE AND A DIP TUBE COMMUNICATION WITH SAID SAMPLING VALVE AND EXTENDING INTO SAID REACTION VESSEL WHEN SAID VALVE MECHANISM IS FITTED TO THE MOUTH OF SAID REACTION VESSEL, SAID SAMPLING VALVE BEING ARRANGED SO THAT IN ONE POSITION COMMUNICATION BETWEEN THE UPPER END OF THE DIP TUBE AND THE SAMPLE REMOVAL CONTAINER MEANS IS ESTABLISHED AND IN ANOTHER POSITION COMMUNICATION BETWEEN THE UPPER END OF THE DIP TUBE AND THE BLEED VALVE IS ESTABLISHED, WHEREBY SAMPLES OF THE MEDIUM IN THE REACTION VESSEL CAN BE REMOVED INTO SAID SAMPLE REMOVAL CONTAINER MEANS BY SIMPLE MANIPULATION OF SAID BLEED VALVE AND SAID SAMPLING VALVE. 